On 7 Nov 2009, at 18:37, inhahe wrote:
> i don't understand this at all
> i hope you will provide a basic explanation of what we're doing for
> us simpletons :P
>
Sure, but next time could you ask a more precise question? ;-)
# Create a pool of threads to execute calls.
with futures.ThreadPoolExecutor(max_threads=5) as executor:
# Schedule the given calls to run using the thread pool created
above and
# return a FutureList (a list of Futures + some convenience
methods). Called
# without the "return_when" argument, waits until all calls are
complete.
futures_list = executor.run_to_futures(...)
# Iterate through every Future. A Future represents one of the
asynchronous
# calls.
for url, future in zip(URLS, future_list):
# Check if the call raised an exception.
if future.exception() is not None:
# Print the exception
print('%r generated an exception: %s' % (url, future.exception()))
else:
# The call returned successfully so future.result() contains the
return
# value.
print('%r page is %d bytes' % (url, len(future.result())))
Cheers,
Brian
> import futures
> import functools
> import urllib.request
>> URLS = [
> 'http://www.foxnews.com/',
> 'http://www.cnn.com/',
> 'http://europe.wsj.com/',
> 'http://www.bbc.co.uk/',
> 'http://some-made-up-domain.com/']
>> def load_url(url, timeout):
> return urllib.request.urlopen(url, timeout=timeout).read()
>> # Use a thread pool with 5 threads to download the URLs. Using a pool
> # of processes would involve changing the initialization to:
> # with futures.ProcessPoolExecutor(max_processes=5) as executor
> with futures.ThreadPoolExecutor(max_threads=5) as executor:
> future_list = executor.run_to_futures(
> [functools.partial(load_url, url, 30) for url in URLS])
>> # Check the results of each future.
> for url, future in zip(URLS, future_list):
> if future.exception() is not None:
> print('%r generated an exception: %s' % (url,
> future.exception()))
> else:
> print('%r page is %d bytes' % (url, len(future.result())))
>> In this example, executor.run_to_futures() returns only when every
> url has been retrieved but it is possible to return immediately, on
> the first completion or on the first failure depending on the
> desired work pattern.
>> The complete docs are here:
>http://sweetapp.com/futures/>